Chapter 29 Heredity Flashcards
Genetics, Development, and Inheritance
- DNA: Genetic material composed of nucleotides.
- Genes: Nucleotide sequences on DNA coding for specific proteins.
- Chromosomes: Condensed DNA with proteins; humans have 23 pairs (46 total).
- Autosomes: 22 pairs with general information.
- Sex chromosomes: 1 pair (X and Y); males are XY, females are XX.
- Allele: Forms of a gene (e.g., hair color); each person has two.
- Homozygous: Two identical alleles.
- Heterozygous: Two different alleles.
- Dominant allele: Always expressed (uppercase letter, e.g., "B").
- Recessive allele: Masked by dominant allele (lowercase letter, e.g., "b").
- Genotype: Genetic makeup; complete set of chromosomes.
- Phenotype: Physical characteristics (e.g., eye color).
- Karyotype: Chromosomes arranged to diagnose abnormalities.
Patterns of Inheritance
- Dominant/recessive: One allele is fully dominant.
- Incomplete dominance: Intermediate trait expression.
- Codominance: Both alleles expressed.
- Polygenic inheritance: Multiple genes contribute to a trait.
Predicting Inheritance
- Punnett square: Predicts the probability of inheriting traits.
- Pedigree: Charts tracing traits through generations.
Sources of Individual Variation
- Genetic recombination
- Independent assortment in meiosis
- Crossing over: Exchange of genetic material during meiosis I.
- Random fertilization
- Mutation
- Spontaneous mutations: Occur randomly.
- Deletions: Loss of chromosome piece.
- Substitutions: Nucleotide replacement.
- Additions: Added nucleotides.
- Frame shifts: Nucleotide additions or deletions altering triplets.
Sex-Linked Inheritance (X-linked)
- Traits carried on the X chromosome.
- Females can be carriers if one X has a recessive allele.
- Males express the trait if their X chromosome has the recessive allele.
- Examples: hemophilia, muscular dystrophy, color-blindness.
The Human Genome Project
- Project to map the entire human genome (completed in 2003).
- Aims to prevent, cure, or treat genetic disorders.
